Oxidation of aminophenols in acidic and alkaline solutions by oxone: stoichiometry and mechanism

The oxidation process of aminophenols in acidic and alkaline media was investigated in order to better understand their stoichiometry and reaction pathways. The mechanistic contemplation was found to be dependent on hydrogen ion concentration. The reaction behaved as second order in the range of pH 6.0–8.0 and first order in the range of pH 10.5–12.0. The speciation of aminophenols and peroxymonosulfate ion have been explored. The stoichiometry indicates one mole of each ortho-aminophenol (OAP) and para-aminophenol (PAP) reacts with 2 mol of peroxomonosulfate. Besides, mechanism and rate law of the oxidation process of aminophenols have been proposed to explain the pH dependence. A structural investigation of intermediates and degradation products was also carried out. This research may establish a framework for anticipating the oxidation reaction process of different aminophenols in wastewater treatment.